A post at The Luminous Landscape today includes the following:

Just as the question with hard drives is not will they fail, but simply, when, a corollary to this is that if you shoot a lot, at least a couple of times a year you’ll end up with a corrupted memory card.

This happened to me yesterday when I was shooting a seminar session being put on at a local studio. When I got back to my own studio in the evening to copy the files to disk, I found that the card was corrupt. I have no idea why, or how it happened, but there it was. My Mac couldn’t even see the card and mount it, and in the camera (Nikon D300) the display said, no directory, no images.

Rather than despair I simply ran PhotoRescue overnight, and this morning had every single file recovered, including every file that had been on the card from my previous shoot, before I had formatted the card in camera yesterday morning. Simply amazing… [The Luminous Landscape – What’s New]

I’ll second both points. Like hard drives, memory cards do get corrupted and you need to be prepared for this eventuality. When it happened to me – twice this year- PhotoRescue recovered my photographs from the corrupted cards.

(In my case, as soon as I had tried to download the photos using Adobe Bridge, the files all disappeared and it looked like there was only a single file left on the card! As reported above, PhotoRescue not only recovered the photos that I had just made, but even turned up a bunch of older images on the reformatted card! In the end, my “bad card” was actually a problem with a separate firewire device that I had left connected to the computer.)